sullivan



M. P. SULLWAN.

SPARK PLUG. APPHCATION FILED DEC. 31.1918.

Patented Aug. 19, 1919.

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mm Mm IN A PM J UNITED STATES PATENT OFFICE.

YMAURICE P. SULLIVAN, OF TORRINGTON, CONNECTICUT, ASSIGNOR TO SPLITDORF' ELECTRICAL COMPANY, OF NEWARK, NEW JERSEY.

To all whom it may concern:

Be itknown that I MAURICE P. SULLIVAN, a citizen of the United States, residing at Torrington, in the county of Litchfield and State-of Connecticut, have invented certain.

newand. useful Improvements in, Spark- Plugs, of which the following is a specification. p q

My invention relates to a spark plug adapted foruse in connection with an internal con'ibustion engine using high tension currentfor ignition. Internal combustion engines of the type used in airplanes develop large power and on-account of the fact that the engines are running at substantially constantspeed at full load for a number of hours, agiieat amount of heat is developed which seriously affects the spark plugs. The

heat thus developed, together with the high compression ordinarily used in this type of an engine, imposes severe conditions on the spark plugs, and it is the object of my present invention to provide a plug which will stand an excessive amount of heat and compression at: the same time one that will keep itself free. from carbon so that the plug cannot bereadily short circuited.

, These and other objects will be apparent to one skilled inthe art, after a study of the annexed drawing, in which 1 'is a shell threaded at the lower end 2 for screwing into the engine cylinder. The shell 1 carries an electrode 3, usually referred. to as the ground electrode. Theupper'part of'the receive a gland i, which,

shell 1 is adapted to p in my preferred construction," is threaded at 5 into the shell 1. A gasket 6 is used to' make a gas-tight joint. It is to be understood that I may attach the gland to the shell 1 in any other suitable manner. The gland 4 carries a central electrode 7 which is insulated therefrom by insulating material 8, preferably ofmica, which extends substantially the full length of the electrode 7 The thickness of the insulating material 8 is made sufficient to withstand the potential that is applied to the electrode 7. The lower end of the electrode 7 carries an enlarged portion or head 9. In the process of manufacturing, I prefer to upset the head 9 on the electrode 7. A spark point 10 is securely fastened to the head 9 in any suitable man- Carried on the head 9 is a bushing 12. The

Specification r Letters Patent. Pate t d Aug. 19, 1919. Application filed December 31, 1918. serial N... 269,154. I

at 13 while-the lower end 11 of the gland 4 is countersunk at 15 in a similar manner to the countersink 13. Positioned between the end 11 and the bushing 12 is an insulator 16., which, in my preferred form, is of mica. This insulator extendsbeyond the peripheral surface of the end l i and the bushing 12 and has its edges chamfered ofl" to form a somewhat rounded V-shaped edge 17. The upper part of the electrode 7 is threaded to receive a clamping nut '18 and a terminal nut 19. Between the gland 4 and the nut 18 is positioned an insulator 20 which can be madeup of one piece of insulating material, such as porcelain, or may be made up of a series of mica washers.

time a very rigid one and it is also seen that the insulator 8, which insulates the electrode 7 from the gland and bushing is protected by these parts from direct contact with the burning gases in the engine cylinder, as well as from oil and carbon, and I have, therefore, obtained what I term an armored plug.

The object ofthe insulator 16 is to form a carbon breaker. I have found that an insulator, such as mica, when at or above a certain temperature, prevents deposition of car bon and I, therefore, construct the bushing 12 of metal of the right characteristics such thatl'it willponvey the-proper amount of heat'to theyinsulator 16, whose outer edge Ihave chamfered off to provide an edge which can be raised to a temperature such as will prevent carbon from forming .thereon so that I eliminate the danger of carbon forming over the edge of the insulator 16 to make an electrical cross between the bushin 12 and the end 14 of gland 4. I preferabIy provide the chamfers 13 and 15 so as to increase the leakage space between the end 14 and the bushing 12 along the surface of the insulator 8. It will be noted that the surface between the parts where gas leaks may occur have been made relatively large so as to secure considerable area of contact between the parts whereby leakage may be prevented.

The insulator 16 may be constructed or formed so as to have the inner portion adapted to fit the countersunk or chamfered portions 13 and 15,allowance bein made for suitable packing desired. further understood by those skilled in the art, that various other changes and alterations may be made in the details relating to my invention, without departing from the spirit of the same and the scope of the appended claims.

Having thus described my invention, what I claim is 1. In a spark plug, a shell, a land adapted to fit the upper part of said s ell and'having one end extending downward into the shell, a headed electrode passing through said gland and its-extended end but insulated therefrom, a bushing carried by said electrode adjacent-its head, adeviee between said bushing and said gland end for breaking up the contiguity of the surfaces thereof, and means on the outer end of the said' electrode for holding the parts carried by the gland securely thereto- 2. In a spark plug, a shell, a gland adapted to fit the upper part of said shell and having one end extending downward into the shell, a headed electrode passing through said gland and its extended end but insulated therefrom, a bushing carried by said electrode adjacent its head, an insulator positioned between said bushing and gland end and extending beyond the peripheral" surfaces of the gland and bushing toward the interior wall of the shell and means'on the outer end of the electrode for holding the bushing and separating insulator securelyto the gland.-

3. In a spark plug, a shell, a gland adapted to fit the upper part of said shell and having one end extending downward into the shell, a headed electrode passing through said gland and its extended end but insulated therefrom, a bushing carried bysaid electrode adjacent its head, an insulator posi- It will be.

'carried by but insulated from the gland, a

headon said electrode carrying a sparking point, a bushing carried by said head and having its upper part countersunk, an insulator between the said countersunk ends of the gland and bushing and extending beyond their peripheral surface and terminating in a roundedV-shaped edge and means for holding the electrode, bushing and insulator securely to the gland.

5. In a spark plug, a shell, a gland adapted to be fastened to said shell, an insulator p: SSlIig through said gland and extending downward into the shell, a central electrode within said insulator, a metallic armor for said extended insulator end and an insulator between said armor and said gland.

6. In a spark plug, a shell, a gland adapted to be fastened to said shell, an insulator passing through said gland and extending downward into the shell, a central electrode within said insulator, a metallic armor for said extended insulator end and an insulater between said armor and said gland, said insulator having a rim so shaped as to be heated by said armor when the plug is in operation whereby carbon will not form thereon.

In witness whereof, I afiix my signature.

MAURICE P. SULLIVAN.

some: of this parent may be obtained {or five cents each, by addressing the tlommiisionei' of intents,

Washington, D. (3. 

